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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.nfc;
import static com.android.internal.util.Preconditions.checkNotNull;
import android.annotation.Nullable;
import android.app.ActivityManager;
import android.content.Context;
import android.os.RemoteException;
import android.os.SystemProperties;
import android.util.Log;
import java.util.HashMap;
/**
* Provides an interface to read and update NFC unlock settings.
* <p/>
* Allows system services (currently exclusively LockSettingsService) to
* register NFC tags to be used to unlock the device, as well as the ability
* to enable/disable the service entirely.
*
*/
public class NfcUnlock {
/**
* Action to unlock the device.
*
* @hide
*/
public static final String ACTION_NFC_UNLOCK = "android.nfc.ACTION_NFC_UNLOCK";
/**
* Permission to unlock the device.
*
* @hide
*/
public static final String NFC_UNLOCK_PERMISSION = "android.permission.NFC_UNLOCK";
/**
* Property to enable NFC Unlock
*
* @hide
*/
public static final String PROPERTY = "ro.com.android.nfc.unlock";
private static final String TAG = "NfcUnlock";
private static HashMap<Context, NfcUnlock> sNfcUnlocks = new HashMap<Context, NfcUnlock>();
private final Context mContext;
private final boolean mEnabled;
private INfcUnlockSettings sService;
private NfcUnlock(Context context, INfcUnlockSettings service) {
this.mContext = checkNotNull(context);
this.sService = checkNotNull(service);
this.mEnabled = getPropertyEnabled();
}
/**
* Returns an instance of {@link NfcUnlock}.
*/
public static synchronized NfcUnlock getInstance(NfcAdapter nfcAdapter) {
Context context = nfcAdapter.getContext();
if (context == null) {
Log.e(TAG, "NfcAdapter context is null");
throw new UnsupportedOperationException();
}
NfcUnlock manager = sNfcUnlocks.get(context);
if (manager == null) {
INfcUnlockSettings service = nfcAdapter.getNfcUnlockSettingsService();
manager = new NfcUnlock(context, service);
sNfcUnlocks.put(context, manager);
}
return manager;
}
/**
* Registers the given {@code tag} as an unlock tag.
*
* @return true if the tag was successfully registered.
* @hide
*/
public boolean registerTag(Tag tag) {
enforcePropertyEnabled();
int currentUser = ActivityManager.getCurrentUser();
try {
return sService.registerTag(currentUser, tag);
} catch (RemoteException e) {
recoverService();
if (sService == null) {
Log.e(TAG, "Failed to recover NfcUnlockSettingsService");
return false;
}
try {
return sService.registerTag(currentUser, tag);
} catch (RemoteException ee) {
Log.e(TAG, "Failed to reach NfcUnlockSettingsService", ee);
return false;
}
}
}
/**
* Deregisters the given {@code tag} as an unlock tag.
*
* @return true if the tag was successfully deregistered.
* @hide
*/
public boolean deregisterTag(long timestamp) {
enforcePropertyEnabled();
int currentUser = ActivityManager.getCurrentUser();
try {
return sService.deregisterTag(currentUser, timestamp);
} catch (RemoteException e) {
recoverService();
if (sService == null) {
Log.e(TAG, "Failed to recover NfcUnlockSettingsService");
return false;
}
try {
return sService.deregisterTag(currentUser, timestamp);
} catch (RemoteException ee) {
Log.e(TAG, "Failed to reach NfcUnlockSettingsService", ee);
return false;
}
}
}
/**
* Determines the enable state of the NFC unlock feature.
*
* @return true if NFC unlock is enabled.
*/
public boolean getNfcUnlockEnabled() {
enforcePropertyEnabled();
int currentUser = ActivityManager.getCurrentUser();
try {
return sService.getNfcUnlockEnabled(currentUser);
} catch (RemoteException e) {
recoverService();
if (sService == null) {
Log.e(TAG, "Failed to recover NfcUnlockSettingsService");
return false;
}
try {
return sService.getNfcUnlockEnabled(currentUser);
} catch (RemoteException ee) {
Log.e(TAG, "Failed to reach NfcUnlockSettingsService", ee);
return false;
}
}
}
/**
* Set the enable state of the NFC unlock feature.
*
* @return true if the setting was successfully persisted.
* @hide
*/
public boolean setNfcUnlockEnabled(boolean enabled) {
enforcePropertyEnabled();
int currentUser = ActivityManager.getCurrentUser();
try {
sService.setNfcUnlockEnabled(currentUser, enabled);
return true;
} catch (RemoteException e) {
recoverService();
if (sService == null) {
Log.e(TAG, "Failed to recover NfcUnlockSettingsService");
return false;
}
try {
sService.setNfcUnlockEnabled(currentUser, enabled);
return true;
} catch (RemoteException ee) {
Log.e(TAG, "Failed to reach NfcUnlockSettingsService", ee);
return false;
}
}
}
/**
* Returns a list of times (in millis since epoch) corresponding to when
* unlock tags were registered.
*
* @hide
*/
@Nullable
public long[] getTagRegistryTimes() {
enforcePropertyEnabled();
int currentUser = ActivityManager.getCurrentUser();
try {
return sService.getTagRegistryTimes(currentUser);
} catch (RemoteException e) {
recoverService();
if (sService == null) {
Log.e(TAG, "Failed to recover NfcUnlockSettingsService");
return null;
}
try {
return sService.getTagRegistryTimes(currentUser);
} catch (RemoteException ee) {
Log.e(TAG, "Failed to reach NfcUnlockSettingsService", ee);
return null;
}
}
}
/**
* @hide
*/
public static boolean getPropertyEnabled() {
return SystemProperties.get(PROPERTY).equals("ON");
}
private void recoverService() {
NfcAdapter adapter = NfcAdapter.getDefaultAdapter(mContext);
sService = adapter.getNfcUnlockSettingsService();
}
private void enforcePropertyEnabled() {
if (!mEnabled) {
throw new UnsupportedOperationException("NFC Unlock property is not enabled");
}
}
}
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